Comparison of the electronic structure of AlPd andAl70Pd20

The electronic structure of crystalline AlPd and quasicrystalline ${\mathrm{Al}}_{70}$${\mathrm{Pd}}_{20}$${\mathrm{Mn}}_{10}$ has been investigated by x-ray photoelectron and electron energy-loss spectroscopy. The spectral shape of the Pd-derived 4d states in the valence-band region and the 3d core-level shifts are identical in both alloys, suggesting similar local environments for Pd atoms, both chemically and structurally. Although the macroscopic crystal structure is essentially different, these alloys have remarkably similar electronic properties determined by the Al-Pd interaction. In both materials, the spectra display a satellite at an energy of approximately 20 eV, accompanying all excitations, which is localized at the Pd site, whereas plasmon losses characteristic of pure Al are strongly suppressed. The Al-Mn interaction in the quasicrystal causes minor changes in the Al core levels and in the valence band by increasing the density of states at the Fermi level.